U.S. patent number RE38,221 [Application Number 09/943,098] was granted by the patent office on 2003-08-19 for 300 mm microenvironment pod with door on side.
This patent grant is currently assigned to Entegris, Inc.. Invention is credited to Gary Gallagher, Barry Gregerson, Brian Wiseman.
United States Patent |
RE38,221 |
Gregerson , et al. |
August 19, 2003 |
300 mm microenvironment pod with door on side
Abstract
A container for creating a microenvironment is disclosed. The
container includes a shell, a door and a plurality of supports
having a unique design which are used to securely retain items,
such as silicon wafers, in a spaced apart parallel relationship.
The supports are removable. An electrical path is provided to
ground the supports. Kinematic coupling structures are also
provided for positioning the container on a surface so as to, for
example, properly align the door with the port of a wafer
processing tool.
Inventors: |
Gregerson; Barry (Deephaven,
MN), Gallagher; Gary (Austin, TX), Wiseman; Brian
(Oakdale, MN) |
Assignee: |
Entegris, Inc. (Chaska,
MN)
|
Family
ID: |
22249868 |
Appl.
No.: |
09/943,098 |
Filed: |
August 30, 2001 |
PCT
Filed: |
October 13, 1995 |
PCT No.: |
PCT/US95/12516 |
PCT
Pub. No.: |
WO97/13710 |
PCT
Pub. Date: |
April 17, 1997 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
913260 |
Sep 10, 1997 |
05944194 |
Aug 31, 1999 |
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Current U.S.
Class: |
206/711;
206/454 |
Current CPC
Class: |
H01L
21/67383 (20130101); H01L 21/67379 (20130101); H01L
21/67369 (20130101); H01L 21/67396 (20130101); H01L
21/67763 (20130101); G11B 33/14 (20130101); G11B
33/0405 (20130101) |
Current International
Class: |
H01L
21/67 (20060101); H01L 21/673 (20060101); H01L
21/677 (20060101); B65D 085/90 () |
Field of
Search: |
;53/467,471
;29/428,525.01,525.08,525.11
;206/454,701,709,710-712,719,723,832,833,525,526 ;211/41.18 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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57113446 |
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Jul 1982 |
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JP |
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6349387 |
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Apr 1988 |
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JP |
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6437047 |
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Jun 1989 |
|
JP |
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6283486 |
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Jul 1994 |
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JP |
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Primary Examiner: Foster; Jim
Attorney, Agent or Firm: Patterson, Thuente, Skaar &
Christensen, P.A.
Parent Case Text
.Iadd.Notice: More than one reissue application has been filed for
the reissue of U.S. Pat. No. 5,944,194. The reissue applications
are application Ser. No. 10/310,069, filed Dec. 4, 2002, a
continuation of the present application, Ser. No. 09/943,098, which
is a reissue of U.S. Pat. No. 5,944,194..Iaddend.
Claims
What is claimed is:
1. A container for creating a microenvironment which protects items
stored therein from damage, said container including: (a) a shell
having an opening for insertion and removal of items from said
shell, said shell made of a material which inherently possess a
slightly negative electrical charge; (b) a pair of supports which
cooperate to retain a plurality of items stored in the container in
a parallel, spaced apart position with respect to each other; (c) a
door for sealing said opening of said shell to prevent
contamination of the items stored in said shell; and (d) means for
creating an electrical path through which such supports are
grounded so that particles within the shell are drawn away from
said items and supports and toward the shell of said container.
2. The container of claim 1, wherein said items stored in the
container are semiconductor wafers.
3. The container of claim 1 further including a pair of handles
located on opposite sides of the container's center of gravity.
4. The container of claim 3 wherein each of said handles has a
groove including an alignment notch so that the handle can be
securely gripped by a robot.
5. The container of claim 1 further including a kinematic coupling
plate secured to the exterior of said shell by a plurality of
posts, said kinematic coupling plate having three alignment grooves
each of said alignment grooves having a cross section which is
generally a Y-shape.
6. The container of claim 5 wherein said alignment grooves of said
kinematic coupling plate are used to align the container door with
the port of a tool used to process semiconductor wafers so that a
seal is created around the shell's opening and the tool's port
before the container's door is opened and the wafers are withdrawn
from the shell, through the port, and into the tool for
processing.
7. The container of claim 1 further including a kinematic coupling
plate secured to the exterior of the shell, said kinematic coupling
plate being made of an electrically conductive material.
8. The container of claim 7 wherein said means for creating an
electrical path through which the supports are grounded includes an
electrically conductive connection between each of said supports
and said kinematic coupling plate.
9. The container of claim 1 wherein said door includes means on its
exterior surface for coupling said door to another surface.
10. The container of claim 1 wherein each of said supports is
releasably secured to the shell so that such supports can be
removed for cleaning or replacement.
11. The container of claim 2 wherein said supports have a plurality
of channels, each of said channels having a backside which is
curved in the circumferential direction.
12. The container of claim 11 wherein the radius of curvature of
the backside of said channels in the circumferential direction is
generally the same as the radius of curvature in the
circumferential direction of said wafers.
13. The container of claim 2 wherein each of said pair of supports
include a plurality of wafer dividers, each of said wafer dividers
having a continuously varying slope to help support one of said
semiconductor wafers.
14. A container for creating a microenvironment which protects
items stored therein from damage, said container including: (a) a
shell having an opening for insertion and removal of items from
said shell; (b) a pair of supports which cooperate to retain a
plurality of items stored in the container in a parallel, spaced
apart position with respect to each other, each of said supports
having a plurality of channels, each of said channels having a
backside, at least a portion of which is curved in the
circumferential direction; (c) a door for sealing said opening of
said shell to prevent contamination of the items stored in said
shell; and (d) means for kinematically coupling said container to
another surface.
15. The container of claim 14 wherein the curved portion of the
backside of each channel has a radius of curvature in the
circumferential direction which is generally the same as the radius
of curvature in the circumferential direction of the items to be
stored.
16. The container of claim 14 wherein said supports are releasably
secured to said shell.
17. The container of claim 14 further including means for providing
an electrical path through which said supports are electrically
grounded so that particles within the shell are drawn away from
said items and supports and toward the shell of said container.
18. The container of claim 14 wherein said means for kinematically
coupling said container to said surface includes at least three
grooves on said container which each mate with separate projections
on said surface.
19. The container of claim 14 wherein said means for kinematically
coupling said container to said surface includes at least three
projections on said container with each mating with separate
grooves on the surface.
20. The container of claim 14 wherein said door has a cushion on
its interior surface which assists said pair of supports to reduce
movement and vibration of items stored in the container during
transport.
21. The container of claim 14 wherein each of said pair of supports
have a plurality of dividers, each divider shaped to have a
continuously varying slope to help support a wafer..Iadd.
22. A container for creating a microenvironment which protects
items being stored therein from damage, said container comprising:
a shell including a shell opening, the shell comprising an
inherently negatively charged material; a pair of grounded supports
cooperating to retain a plurality of items stored in the container,
said supports in a generally parallel, spaced apart position with
respect to each other; and a door configured for sealing said shell
opening..Iaddend..Iadd.
23. The container of claim 22, further comprising a kinematic
coupling plate and a plurality of screws, said plurality of screws
forming a conductive path between the supports and the kinematic
coupling plate..Iaddend..Iadd.
24. The container of claim 23, the kinematic coupling plate
comprising a plurality of receiving members, each of said receiving
members receiving one of said plurality of
screws..Iaddend..Iadd.
25. The container of claim 22, wherein each of said items stored in
the container are semiconductor wafers..Iaddend..Iadd.
26. The container of claim 22, further comprising a kinematic
coupling plate secured to the exterior of said shell by a plurality
of posts, said kinematic coupling plate comprising three alignment
grooves, each of said alignment grooves including a generally
Y-shaped cross section..Iaddend..Iadd.
27. The container of claim 22, further comprising a kinematic
coupling plate secured to the exterior of the shell, the kinematic
coupling plate comprising an electrically conductive
material..Iaddend..Iadd.
28. The container of claim 22, said door comprising means for
coupling said door to another surface..Iaddend..Iadd.
29. The container of claim 28, wherein said coupling means is
disposed on an exterior surface of said door..Iaddend..Iadd.
30. The container of claim 22, each of said supports releasably
secured to said shell..Iaddend..Iadd.
31. The container of claim 22, each of said supports defining a
plurality of channels, each of said plurality of channels having a
backside curved in a circumferential direction..Iaddend..Iadd.
32. The container of claim 31, in which each of said channel
backsides is characterized by a channel backside radius, each said
channel backside radius generally equal to a radius of curvature of
said items being stored in said container..Iaddend..Iadd.
33. The container of claim 22, each of said supports comprising a
plurality of dividers, each of said plurality of dividers having a
continuously varying slope..Iaddend..Iadd.
34. A method of storing a plurality of items in a container, the
container comprising a shell, a pair of grounded supports, and a
door, the shell with a shell opening for insertion of the items
into the shell and for removal of the items from the shell, the
shell comprising an inherently negatively charged material, the
supports cooperating to retain the plurality of items stored in the
container in a generally parallel, spaced apart position with
respect to each other, the door configured for sealing the shell
opening, the method comprising: placing a first of the items into
the shell; and sealing the shell opening with the
door..Iaddend..Iadd.
35. The method of claim 34, further comprising placing a second of
the items into the shell, such that the first and second items are
in a spaced apart, generally parallel
relationship..Iaddend..Iadd.
36. The method of claim 34, wherein sealing the shell opening with
the door comprises supporting each of the items in the shell with
three areas of support..Iaddend..Iadd.
37. The method of claim 34, wherein placing said first of the items
into the shell comprises contacting said first of the items and the
pair of supports..Iaddend..Iadd.
38. The method of claim 37, the container further comprising an
electrically conductive kinematic plate and at least one screw,
said at least one screw providing an electrically conductive
pathway between the support and the kinematic plate, and wherein
placing said first of the items into the shell comprises grounding
the first of said items..Iaddend..Iadd.
39. The method of claim 38, further comprising aligning the shell
opening with a processing equipment port..Iaddend..Iadd.
40. The method of claim 39, the kinematic plate having a plurality
of kinematic plate grooves and in which aligning the shell opening
with the processing equipment port includes mating the kinematic
plate grooves with processing equipment posts..Iaddend..Iadd.
41. A method of making a container, comprising: forming a
negatively charged shell with a shell opening; disposing a pair of
electricly conductive supports in the shell; forming a door
configured to seal the shell opening; and grounding the
supports..Iaddend..Iadd.
42. The method of claim 41, in which the supports are electrically
coupled to a kinematic coupling plate..Iaddend..Iadd.
43. The method of claim 42, in which the supports are electrically
coupled to the kinematic coupling plate by at least one
screw..Iaddend..Iadd.
44. The method of claim 41, in which grounding the supports
comprises electrically connecting the supports to a kinematic
coupling plate with a screw..Iaddend..Iadd.
45. The method of claim 41, in which disposing the pair of supports
in the shell includes electrically insulating the pair of supports
from the shell..Iaddend.
Description
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates generally to a package for an item.
More particularly, the present invention relates to a package
specifically designed to isolate from contamination materials used
in the manufacture of electronic semiconductor components and
circuits. Such packages are particularly well suited for
substrates, wafers, memory disks, photomasks, flat panel displays,
liquid crystal displays, and the like.
II. Description of the Prior Art
Various containers have been used for centuries to transport items
from one place to another. Such containers have, for example, been
used to provide a way to confine items in a space for efficient
storage. Such containers also provide an easy way of handling
items. Another important function provided by packages and
containers is protection.
Substrates used in the manufacture of semiconductor circuits, rigid
memory disks, photomasks, liquid crystal displays, and flat panel
displays can be extremely sensitive. Effective steps must be taken
to protect such items from damage by moisture, particles, static
electricity, or the like. Steps must also be taken to protect the
articles from damage caused by vibration and shock within the
package. Similarly, steps must be taken to prevent outgassing and
the generation of particles which will occur if the items stored in
the package scrape, rub, or impact various surfaces within the
package.
This combination of problems makes designing a suitable package
very difficult. Such problems are only compounded by the
environment in which such packages are typically used.
Suitable packaging for use in connection with the storage and
transport of wafers, memory disks, photomasks, liquid crystal
display panels and flat panel displays tend to be very expensive.
It is highly desirable that such packaging be reusable and have
durable construction. Also, such packaging must be capable of being
readily and thoroughly cleaned. Finally, when the package is used
in connection with the manufacture of semiconductors, it must be
readily adaptable for use with robotic handling and automated
manufacturing equipment.
Empak, Inc., has made a number of suitable packages in the past for
use in the processing and transport of such items. Examples of such
packages are shown in U.S. Pat. No. 5,273,159 and U.S. Pat. No.
5,423,422. While such package designs have proven to be highly
effective in conjunction with smaller items, the designs, for a
variety of reasons, are not suitable for storage and transport of
items having outside dimensions in the range of 300 mm or more.
SUMMARY OF THE INVENTION
Suitable containers for use with wafers, photomasks, memory disks,
liquid crystal display panels and flat panel displays must meet
several important design criteria. They must be light weight to
make manual and robotic handling tasks easier. The internal volume
of the container should be minimized to reduce storage space
requirement and increase storage density. The height of the
container should be minimized to allow for improved stacking of the
containers. The amount of polymer surface area surrounding the
items during transport and storage should be minimized to reduce
inorganic and organic contaminants as well as the negative affects
of outgassing of the polymer.
Containers built in accordance with the present invention meet the
design criteria set forth above. Such containers also provide
several other unique advantages. First, tolerance build-up is
minimized by means of locating the container about item center
lines, thereby increasing the positional accuracy of the items
stored in such containers. This enhances effective insertion and
removal of the items from the container using robotic equipment.
Second, the containers reduce the risk of damage caused by static
electricity. This is achieved in one preferred embodiment by
providing a conductive path to ground from static dissipative
internal item supports to the container's external kinematic
coupling plate which is used to position the container on various
pieces of equipment. Third, the containers of the present invention
are designed to be wet-cleaned with or without disassembly. Fourth,
since the containers of the present invention can have an integral
design which does not require a separate carrier, the containers
can remain associated with a specific lot of items. This enables
workers in the factory to better track a lot and, therefore,
reduces the chance of processing errors. Fifth, the integral
design, by eliminating the need for a separate cassette, minimizes
the number of packaging components required to be kept in inventory
and the space such components take up. Sixth, the integral design
eliminates the need to accurately position a removable cassette in
the container and lock it in place. Finally, the integral design
can be manufactured using fewer and smaller parts, thereby reducing
manufacturing costs.
It is therefore an object of the present invention to provide an
isolation container which will provide protection against
contamination by particles or moisture.
Another object of the present invention to provide a container
which protects the items stored therein from damage due to shock
and vibration and from damage due to the item scraping, rubbing, or
impacting various surfaces of the container.
A further object of the invention is to provide such a container
which is reusable and easily cleaned.
Still another object of the invention is to provide such a
container which has interior structures which are not susceptible
to wear or generation of particles which could contaminate the
contents of the package.
Yet another object of the invention is to provide such a container
which is highly effective when used in conjunction with automated
processing or handling equipment.
Still another object of the invention is to provide a structure
which can easily be handled, manipulated and transported by
humans.
These and other objects are accomplished by providing a container
having a shell with an opening for insertion and removal of the
items, a door designed to effectively seal the opening, a plurality
of item-retaining structures within the shell which securely hold
the items and retain them in spaced apart relation from each other,
a kinematic coupler plate to assist in aligning the container with
the port of equipment used to process the items in a factory, and
ergonomically designed handles which can be effectively used either
manually or through robotic means. In order to reduce contamination
by particles inside the container, the item supports are made of a
high-temperature resistant, conductive material. The item supports
are also grounded to the exterior of the container as described in
detail below. The entire container is structured to maximize the
support and protection offered to the items, maximize ease of
handling, and reduce, to the extent possible, the height and weight
of the container.
A better understanding of the invention will be deserved from
reading the description of the preferred embodiment set forth below
in conjunction with the drawings. While the description and
drawings specifically relate to a microenvironment pod for silicon
wafers, the invention described is also well suited for other
applications, such as the storage and transport of photomasks,
rigid memory disks, liquid crystal display panels, flat panel
displays, or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a container shell made in
accordance with the invention;
FIG. 2 is a top plan view of the container shell;
FIG. 3 is a cross-section of the container through line A--A in
FIG. 2;
FIG. 4 is a cross-section of the container through line B--B in
FIG. 2;
FIG. 5 is a side view of the container incorporating the present
invention;
FIG. 6 is a cross-section of the container through line C--C in
FIG. 5;
FIG. 7 is a view of the container from the side opposite the
door;
FIG. 8 is a drawing of the kinematic coupler plate;
FIG. 9 is a cross-section of the kinematic coupler plate through
line D--D in FIG. 8;
FIG. 10 is a cross-section of the kinematic coupler plate through
line E--E in FIG. 8;
FIG. 11 is a cross-section of the kinematic coupler plate through
line F--F in FIG. 8;
FIG. 12 is a prospective view of one of the ergonomic handles used
in the design;
FIG. 13 is an end view of the handle;
FIG. 14 is a cross-section of the handle through line G--G in FIG.
13;
FIG. 15 is a plan view of the door of the container in the closed
position with respect to the container's shell;
FIG. 16 is a perspective view of a cushion which can be attached to
the inside surface of the door to help support and retain items
stored in the container in the proper position during storage and
transport; and
FIG. 17 is a cross section showing two opposing dividers and a
wafer.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, the container of the present invention has an
exterior shell 10. The exterior shell 10 has six sides 12, 14, 16,
18, 20 and 22.
Side 12 comprises a door frame 6 having a pair of opposing end
portions 7 and a pair of side portions 8. Sides 14 and 16 of the
exterior shell 10 are defined generally by straight walls extending
from the opposite end portions 7 of the door frame 6. Wall 18
extends between walls 14 and 16 and is in the shape of a partial
cylinder. The radius of curvature of wall 18 is generally the same
as the radius of curvature of the wafer to be stored in the
container. Top and bottom walls 20 and 22 complete the shell. Walls
20 and 22 have a generally flat surface 24 and a reinforcement
member 26 projecting outwardly from the flat surface 24.
Reinforcement member 26 prevents warpage of the container and
especially walls 20 and 22. Reinforcement members 26 have four legs
28, 30, 32 and 34. Extending across wall 18 between the two legs 30
is a cross-brace 31. In a similar fashion, cross-brace 33 extends
between the two legs 32. Cross-braces 31 and 33 can be used to
support the exterior shell 10 on a flat surface if it is positioned
so that wall 18 is down.
Also shown in FIG. 1 is a kinematic coupling plate 40. FIGS. 1-5
and 8-11 show the structure of the kinematic coupling plate in
greater detail. This plate is secured to wall 20 by a plurality of
mounting posts 42 (see FIG. 5). Three separate coupling grooves 44,
45 and 46 are formed into the kinematic coupling plate 40. These
grooves are designed to mate with posts on the processing equipment
(not shown) to align the access opening 8 with a port on the
processing equipment. As best shown in FIG. 10, the grooves 44, 45
and 46 are Y-shaped to include a narrow, deeper, center channel 47
and wider, less deep, upper channel 48 which serves to catch and
direct the alignment post of the processing equipment into the
center channel 47 to achieve proper alignment. Proper alignment
results when the three alignment posts on the processing equipment
(not shown) mate with the center channel 47 of the grooves 44, 45
and 46.
The kinematic coupling plate 40 is made of a conductive material.
It is also designed to include a pair of screw receiving members
49. As explained below, members 49 each receive a screw which is
used to electrically couple the kinematic coupling plate 40 to the
wafer supports 60 located inside the container. This electrical
coupling creates a path by which the wafer supports can be grounded
to dissipate any electrical charge on the wafers or wafer supports
and, thus, prevent damage to the wafers caused by static
electricity.
FIG. 1 also shows a pair of handles 50. These handles are located
at the center of gravity of the container. The handles are
ergonomically designed so they are easily gripped from a variety of
angles by the human hand. The design of the handles 50 allows them
to be effectively grasped by robotic handling equipment.
More specifically, each handle 50 includes a support column 51
which joins the handle 50 to the shell 10 and a wider gripping
member 52. The gripping member 52 has an exterior shape which
permits it to be comfortably grasped by a human hand. The gripping
member 52 also has a recessed channel formed in its end. Channel 53
is generally straight, but includes a notch 54. The channel 53 and
notch 54 are present to be engaged by gripping members of a robotic
arm. As such, the container is designed for easy, efficient and
safe handling by humans or robots.
FIGS. 3, 4 and 6 show some of the interior structure of the shell
10 not visible in FIG. 1. For example, FIGS. 3 and 4 show wafer
supports 60 and 62 which cooperate to hold up to thirteen wafers
80. Typically, twelve of the wafers 80 are product wafers and one
is a test wafer. The wafer supports 60 and 62 are all made of a
material which is electrically conductive and resistant to high
temperatures. The wafer supports 60 and 62, as shown, each have
fourteen wafer dividers 65. A wafer edge receiving channel 66 is
formed between each pair of dividers 65. The channels on wafer
support 60 cooperate with the channels on wafer support 62 to hold
the wafers 80 in a parallel spaced apart registration as shown in
FIGS. 3 and 4. Those skilled in the art will recognize that the
wafer supports 60 and 62 can be modified to hold more wafers (for
example, 25) or fewer wafers (for example, 7) without deviating
from the present invention. Likewise, the wafer supports 60 and 62
could also be dimensioned to retain something other than a wafer or
to retain wafers of differing sizes.
In the preferred embodiment shown in the drawings, each of the
channels 66 is especially formed to retain 300 mm wafers. The back
side of each channel is curved in the circumferential direction
(e.g. the direction of the circumference of the wafer 80) and in
the transverse direction (e.g., the direction across the thickness
of the wafer 80). The curvature of the backside of each channel 66
is approximately the same radius of curvature as the outside edge
of the 300 mm wafers 80, in both the circumferential and transverse
directions. Providing the same radius of curvature along the
circumferential direction presents contact between the channel's
back side and the edge of the wafer 80 along an arc rather than
merely at a point.
Significant advantages are provided by shaping the wafer divider 65
as shown in FIG. 17. The wafer dividers have a continuously varying
slope such that gravity helps center the wafer 80 in the middle of
the carrier. With this style of wafer divider 65, the wafer always
rests on a portion of the wafer divider that has a finite slope, so
edge contact is guaranteed. Further, if for any reason the wafer is
moved off of dead center, one edge is raised more quickly than the
other edge is lowered. Thus, for carriers where the wafers are
transported horizontally, gravity may be used to help center the
wafer with this support. Once centered, the wafer's vertical
location is precisely defined. As the carrier is moved from one
location to the next, small levels of vibration may help to center
the wafer in the carrier, thus improving the horizontal positional
accuracy of the wafers as well as the vertical positional
accuracy.
An additional benefit of the wafer design, as shown in FIG. 17, is
that it presents the lowest possible cross-section for a given
support strength. The divider 65 presents an area of interference
for the wafer 80 as it is inserted into and removed from the
carrier. Thin dividers are preferred because there is less chance
of a wafer 80 hitting the divider and causing particles to be
generated. On the other hand, the divider 65 must be thick enough
to support the wafer 80 and to avoid deflection over the life of
the container. In light of these conflicting requirements, the
divider design has a continuously varying angle as shown in FIG.
17.
In the preferred embodiment, a pair of screws 64 are provided. One
of the screws 64 is used to form a conductive path between the
wafer support 60 and the conductive kinematic coupling plate 40.
The other screw 64 is used to provide a conductive path between
wafer support 62 and the kinematic coupling plate 40. This
arrangement provides the advantage of grounding the wafer supports
60 and 62 via screws 64 and the kinematic coupling plate 40 so that
the wafer supports 60 and 62 have no electrical charge. The walls
of the shell 10 are not grounded and have a slightly negative
charge which will cause particles in the container to migrate and
attach themselves to the walls of the container where they can do
no harm to the wafers. So that the screws 64 do not ground the
exterior shell 10, it may be desirable to line the bores in the
shell 10 through which the screws 64 pass with an insulative
material.
To close the access opening 8 of the shell 10, a door 90 is
provided. The door 90 is shaped and dimensioned to fit within the
door frame 6. When in place, the door engages the door frame 6 to
seal the container. Likewise, the outer edge of door frame 6 can be
used to form a seal around the access opening 8 between the door
frame 6 and the port of a tool used to process semiconductor wafers
80. The risk of contamination is reduced if such a seal is created
before the door 90 is opened. When such a seal is created, the door
90 can safely be opened so that the wafers 80 can be withdrawn from
the shell 10, through the port and into the tool for processing
without substantial risk of contamination. Typically, a plurality
of latches (not shown) to hold the door in the closed position will
be provided. Also, a flexible gasket or ring can be provided
between the door 90 and frame 6 to ensure complete sealing between
the door 90 and frame 6.
The door 90 can be provided with a wafer cushion 92. As shown in
FIG. 16, cushion 92 has a pair of rigid rails 93 and 94 and a
plurality of deformable cross-members 95. Thirteen deformable
cross-members 95 are shown in FIG. 16. Each cross-member 95 has a
pair of dividers 96. Each divider 96 is aligned with a divider 97
on rigid rail 93 and a divider 98 on rigid rail 94. Thus, as the
door 90 is closed, the wafers 80 engage the channels formed by the
dividers 96, 97 and 98. Cross-members 95 will deform until the
edges of wafers 80 also engage the rigid rails 93 and 94. Even if
the wafers 80 are jarred during transport, contact with and support
by cushion 92 is not lost because of the deformable cross-members
95.
The inclusion of such a wafer cushion 92 on the door 90 yields
three areas of support for the wafers 80, thereby reducing movement
and vibration of the wafers 80 during transport. Supporting the
wafers 80 in three areas reduces damage to the wafers due to
scraping, rubbing or impacting surfaces within the container. It
also limits generation of particles due to such scraping, rubbing
or impacting. Finally, means can be provided on the exterior door
for kinematically coupling the door 90 to another surface. This can
be a series of three grooves (not shown) similar to those shown in
kinematic coupling plate 40 which mate with projections on the
surface of three projections on the door 90 which mate with grooves
on the surface.
Although the present invention has been illustrated and described
with reference to the preferred embodiment thereof, the invention
may also be used in conjunction with the transport and storage of
liquid crystal displays, flat panel displays, photomasks, rigid
memory disks, substrates, and the like. Also, various components of
the invention may be constructed so that they are removable and
replaceable to extend the life of the container. This is certainly
true of the wafer supports 60 and 62 and wafer cushion 92 which can
be removed and replaced with supports or cushions more ideally
suited for other items to be held in the container. It should be
understood, therefore, that the illustrations and descriptions
provided herein are not intended to be limiting and that numerous
modifications can be made within the scope of this invention and
the claims set forth below.
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